Ventilatory instrument for measuring peak expiratory flow



FIG. 1 is a front elevational view of a ventilatory instrument for measuring peak expiratory flow showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right side elevational view thereof, the left side elevational view being a mirror image;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a ventilatory instrument for measuring peak expiratory flow, as shown and described. 